. Stock cranks are actually case nitride hardened up to 3mm deep. You can certainly grind the crank with no adverse effects so long as the finish of the journals are correctly done.
I once long ago too thought the factory nitride saturation levels were low but after doing development on vg components I've found the factory crank is nitride hardened quite a bit. If you're skeptical simply grind the crank and send out to be rewarded. Don't be afraid to do so. I will say there's no reason the grind the unless the journal is physically damaged to the point a typical .010 can be ground down to promote a new journal dimension